Electronic devices continue to become smaller due to improvements in integration and overall system design. While the electronic devices continue to get smaller, their functionality continues to increase. For example, handheld wireless devices, such as cellular telephones, personal digital assistants (PDA), portable computers, pagers, and so forth, have begun to converge, wherein a single electronic device may have built-in cellular telephone, personal digital assistant, limited computing, paging, and so on, capabilities. Additionally, communications devices, such as cellular telephones, are now capable of communicating in multiple communications protocols and over different frequency bands.
The increased number of communications protocols and the different frequency bands utilized by the different communications protocols may present an interference problem. Transmissions and receptions at the various frequency bands using the different communications protocols may interfere with each other. For example, in a wireless device that may be capable of communicating in the Enhanced Data rates for GSM Evolution (EDGE) communications protocol and over the Personal Communications System (PCS) band, transmitting an EDGE signal in a first channel containing sigma-delta modulation, the noise shaping present in sigma-delta modulated data carried within the EDGE signal will result in a higher than permitted noise level in the Industrial, Scientific, and Medical (ISM) band.
Consequently, the noise shaping in the sigma-delta modulated data may need to be modified so that the interference caused in the ISM band is no longer an issue. Alternatively, comb filters may be added to help eliminate the noise shaping in the sigma-delta modulated data that is causing interference with the ISM band. However, the addition of the comb filter may negatively affect the resolution of the transmissions of the wireless device. For example, if the comb filter includes two fingers, the resolution may be decreased by a factor of two, plus there may be a one-delayed version of the data for which compensation must be provided, which may yield a loss in resolution of one bit. If the comb filter includes four fingers, then the resolution may be decreased by a factor of four and a three-delayed version of the data for which compensation must be provided, which may yield a loss in resolution of two bits.